ASE A7 Test Prep (HVAC)

Defective thermostat

A customer complains about constant heat out of the air ducts with normal air conditioning pressures and operation. All of the following could be the cause, EXCEPT: a. Blend door adjustment b. Defective heater control valve c. Defective thermostat d. Heater control cable adjustment

Technician A only

A manual AC system is being checked for proper operation. Technician A says when selecting the DEF (defrost position), the AC compressor should be on. Technician B says that recirculation air will also operate in the DEF. Which technician is correct ?

Remove the trapped refrigerant

After waiting the required time for the Recycling/Recovery/Recharging machine to finish, you discover 5 psi in the system. Which of these actions should you follow? a. No action, this is a normal b. The machine is defective call for service. c. There is a leak in the system and air has entered the system. d. Remove the trapped refrigerant

Evacuating system removes moisture from a saturated receiver/dryer

All of the following issues regarding a receiver/dryer are correct, EXCEPT: a. Clogged filter can cause higher than normal pressure b. Saturated desiccant can cause a blockage due to freezing c. You install a new desiccant bag on some systems before charging the system. d. Evacuating system removes moisture from a saturated receiver/dryer

Sound can be heard when a compressor pulley engages and disengages.

All of the following statements related to compressors with damper limiter pulleys are correct, EXCEPT: a. The pulley is attached to the compressor shaft by spokes that break if the compressor locks. b. Sound can be heard when a compressor pulley engages and disengages. c. If the pulley breaks, the compressor and the pulley are replaced as a unit. d. If the pulley breaks, the pulley freewheels on the compressor shaft.

D. You must discharge the refrigeration system before the A/C control panel removal.

All of these statements regarding A/C-heater control panel service are accurate EXCEPT: A. In an air-bag equipped vehicle, you must wait the specified period once the negative battery cable is disconnected. B. The negative battery cable needs to be disconnected before A/C control panel removal. C. Self-diagnostic tests might indicate a defective A/C control panel in the computer-controlled system. D. You must discharge the refrigeration system before the A/C control panel removal.

A. To avoid evaporator odor, you want to operate the AC in RECIRC instead of FRESH

All of these statements regarding an air conditioning performance test are true EXCEPT: A. To avoid evaporator odor, you want to operate the AC in RECIRC instead of FRESH B. Obstructions of the cabin filter might create insufficient air circulation C. Road debris might clog the condenser fins which lead to a decrease in performance D. If the passenger side floor is wet, it could be a clogged evaporator drain line.

Disconnected engine vacuum line

An AC system only blows cold air out of the bottom heater ducts. Which of the following could be the cause? a. Defective evaporator case b. Defective heater core case c. Disconnected engine vacuum line d. Defective thermostat

Both Technician A & B

An ATC (Automatic Temperature Control) system is being diagnosed for a high air outlet temperature. Technician A says it is possible for a malfunctioning ATC control system to prevent correct operation even when the refrigerant system is operating to specs. Technician B says you should use a diagnostic scan tool or laptop computer to identify ATC problems. Which technician is correct ?

Technician B only

An Automatic Temperature Control system that uses a BCM (Body Control Module) is being diagnosed on a 2008 vehicle using a scan tool. Technician A says you need a laptop computer with software to diagnose any of these systems. Technician B says you connect the scan tool, turn on the ignition and use the menus to find your system and tests. Which technician is correct ?

Neither Technician A nor B

An R12 system is being upgraded to R134a. Technician A says hoses replaced on R12 systems must use barrier type hoses. Technician B says non-barrier type hoses use barbed type fittings. Which technician is correct ?

Defective Compressor

An air conditioning system does not cool with the high and low side lines warm to the touch. The low-side pressure is higher than normal with the high-side pressure is lower than normal with the high side gauge needle vibrating. Which of these is the MOST likely cause? a. Stuck closed Expansion Valve b. Defective Compressor c. Overcharged A/C System d. Undercharged A/C System

Technician A only

An engine overheats within the first ten (10) minutes of operation. Technician A says the thermostat is sticking. Technician B says the water pump is slipping. Which technician is correct ?

Recover into a disposable tank

During engine removal and prior to recovering the refrigerant, an unknown refrigerant is found using a refrigerant identifier. What should be done with the refrigerant? a. Discharge into the atmosphere b. Recover into a disposable tank c. Recover and recycle as R-12 d. Recover and recycle as R-134a

Check the air mix door linkage

On a vehicle equipped with a manual temperature control system the discharge air temperature does not change. After checking for service bulletins, which of the following is the next step? a. Check the LAN System circuit b. Check the air mix door linkage c. Check the mode door linkage d. Check the in-car sensor circuit

Technician B only

Technician A says SAE (Society of Automotive Engineers) 5 weight engine oil should be used in R12 systems. Technician B says PAG (Polyalkylene Glycol) or synthetic oil is usually the oil specified by OEMS (original equipment manufacturers) for use in HFC-134a systems. Which technician is correct ?

Both Technician A & B

Technician A says a service technician must wear safety glasses whenever the ACR-4 (recover, recycle, remove and recharge) is connected to the AC system. Technician B says it is against the US Clean Air Act and Montreal Protocol to release R-134a to the atmosphere and is, therefore, a crime. Which technician is correct ?

Technician A only

Technician A says according to EPA Regulations you must have shut-off valves where the R134a service hoses connect to the manifold within 12 inches of service hose ends. Technician B says when charging an R134a system with a sight glass in the receiver/dryer, you add refrigerant until the sight glass is clear. Which technician is correct ?

Technician B only

Technician A says all air conditioning connections use compression fittings to seal the system. Technician B says when replacing O-rings you lubricate the O-ring with the correct refrigerant oil to prevent nicks and ease installation. Which technician is correct ?

Technician B only

Technician A says anytime silicone fluid is leaking out of the radiator fan viscous clutch, the fan clutch must be replaced. Technician B says you should inspect all types of fan blades for stress fractures. Which technician is correct ?

Technician B only

Technician A says dual zone systems separate the zones after the air passes through the heater core. Technician B says dual zone systems have only one evaporator and one heater core. Which technician is correct ?

Technician A only

Technician A says evacuating an AC system removes air and moisture from the system. Technician B says evacuating an AC system removes dirt particles from the system. Which technician is correct ?

Both Technician A & B

Technician A says if both the high-side and low-side gauge pressures are high, the condenser air flow is restricted. Technician B says a worn, glazed or cracked belt can slip, reducing system efficiency, and can cause noises that can be mistaken for a compressor noise. Which technician is correct ?

Technician B only

Technician A says it is alright to replace a vehicles thermostat with one that opens at a lower temperature. Technician B says you can use a scan tool or laptop computer to identify most ATC (automatic temperature control) problems. Which technician is correct ?

Both Technician A & B

Technician A says many O rings and gaskets are specific to R12 and R134a systems because they are made from different material. Technician B says never reuse an O ring or gasket regardless of its appearance. Which technician is correct ?

Both Technician A & B

Technician A says on R134a systems, you may not find any evidence of oil, even with a leak, because the lubricant is water soluble, and could wash away. Technician B says never use compressed air to leak test or pressure test an R134a system. Which technician is correct ?

Technician A only

Technician A says operational checks found in the on-line service information are used to verify which AC functions are working. Technician B says a restricted airflow in a condenser cause low high-side and low-side pressures. Which technician is correct ?

Technician A only

Technician A says the CANDi (Controller Area Network Device Interface) module used on GM vehicles will flash an LED rapidly if communication is detected. Technician B says late model OBD II (on board diagnostic generation II) vehicles use a jumper wire to connect two pins of the Data Link Connector to read Diagnostic Trouble Code on a scan tool. Which technician is correct ?

Technician A only

Technician A says the lower radiator hose contains a spring to prevent it from collapsing and causing a restriction. Technician B says you replace the engine cooling thermostat once a year. Which technician is correct ?

Technician A only

Technician A says the pressure sensor disengages the compressor when low pressure is sensed because low refrigerant flow could result in a lack of lubrication and seize the compressor. Technician B says air conditioning systems using a multi-pressure switch will display a data line for system pressure on the scan tool DATA parameter list. Which technician is correct ?

Both Technician A & B

Technician A says when checking for a leak using an Electronic Leak Detector, you check from the bottom to the top of the AC component area. Technician B says most OEMS (original equipment manufacturers) recommend using an Electronic Leak Detector. Which technician is correct ?

Technician B only

Technician A says you can replace a Schrader type valve core on the low side fitting with one from a vehicle tire Schrader valve. Technician B says R134a refrigerant containers must be EPA approved and are a safety item. Which technician is correct ?

Technician B only

Technician A says you can replace the engine thermostat with one that opens at a lower temperature. Technician B says exhaust emissions affect what thermostat is installed in a cooling system. Which technician is correct ?

Technician A only

Technician A says you can test the intake door position by placing a piece of paper over the intake vent on the cowl. Technician B says the paper will be blown away from the cowl when the system is in the "fresh" position. Which technician is correct ?

Neither Technician A nor B

Technician A says you can use R12 and R134a with the same equipment using a separate set of charging hoses. Technician B says R12 and R134a systems use the same refrigerant oil in the compressor. Which technician is correct ?

Both Technician A & B

Technician A states that when the condenser airflow is restricted, the pressure is high in both the high and low lines. Technician B states that when both high and low sides show low pressure, it's often an indication of low refrigerant. Which technician is correct ?

475 psi (3,275 kPa)

The A/C compressor high-pressure release valve discharges refrigerant at what approximate measurement? A. 200 psi (1,379 kPa) B. 325 psi (2,240 kPa) C. 375 psi (2,585 kPa) D. 475 psi (3,275 kPa)

Low refrigerant level

The AC system has an outside temperature of 85° F and the low -side pressure gauge shows 5 psi with the high-side pressure gauge reading of 105 psi. These readings indicate which of the following? a. High-side restriction b. Low refrigerant level c. Low-side restriction d. Defective compressor

Both Technician A & B

The automatic air conditioning system blows hot air. Technician A says you can use the scan tool or laptop computer snap shot mode to monitor system parameters during a test drive. Technician B says using a digital multimeter (DMM) for diagnosis may not capture intermittent faults. Which technician is correct ?

Technician B only

Two technicians are describing heater diagnosis. Technician A says if one heater hose is hot to the touch and the other hose is cold, then the heater core is functioning okay. Technician B says the upper radiator hose should be at engine operating temperature, which is very hot to the touch. Which technician is correct ?

Technician A only

Water is found dripping under the passenger's side of the vehicle. Technician A says this is a normal condition due to condensation on the evaporator. Technician B says the evaporator housing is defective and needs to be replaced. Which technician is correct ?

Quick-disconnect valves

What type of service valves are used with R-134a? a. Schrader valves b. Gate valves c. Quick-disconnect valves d. Saddle valves

Air gap

Which of the following is the most important measurement done when replacing a compressor clutch? a. Coil voltage drop b. Coil Current (ampere) draw c. Air gap d. Coil resistance

30 minutes, 5 minutes

Which of the following is the smallest amount of time a system is evacuated and the minimum time to hold that vacuum? a. 20 minutes, 10 minutes b. 15 minutes, 5 minutes c. 30 minutes, 5 minutes d. 10 minutes, 10 minutes

500 microns

Which of the following readings represents a very low vacuum or absence of pressure reading? a. 15 inches Hg b. 5,000 microns c. 27 inches Hg d. 500 microns

Infrared Thermometer

Which of the following tools should be used to check the engine cooling system thermostat opening and operating temperature? a. Manometer b. Infrared Thermometer c. Digital Multimeter d. Digital Storage Oscilloscope

Thermal expansion valve (TXV)

While recovering refrigerant, the high-side gauge follows the low-side gauge very quickly with no pressure rise. This test confirms that there is problem in which of the following? a. Condenser b. Suction throttling valve (STV) c. Receiver/dryer d. Thermal expansion valve (TXV)

Variable resistor

9. The electrical symbol in the image represents ?

The refrigerant charge is too low

A "starved" Evaporator is one that has Low Pressure but a "too warm temperature". This is due to what ?

Defective resistors

A blower motor only works on the highest setting. This indicates what ?

True

A clogged orifice tube can cause a lack of cooling. (True or False)

Replace the tensioner

A compressor belt tensioner is bouncing rapidly with the engine running. What should the technician do ?

a normal condition

A container of recovered refrigerant has 91 psi at a temp of 80°F This indicates what ?

Both Technician A & B

A customer complains that when accelerating his car with the A/C on, the cold air flow from the dash outlets shifts to the floor. Technician A says that this is caused by a faulty check valve in the vacuum reservoir. Technician B says that this condition is due to a vacuum leak. Which technician is correct?

Technician A only

A customer complains that when parallel parking the car stalls with the A/C on. Technician A says the power steering pressure switch is bad. Technician B says the problem is with the pump. Which technician is correct?

Both Technician A & B

A gurgling sound is heard coming from inside the dashboard of a vehicle. Technician A says this is air trapped in the heater core. Technician B says this noise can be caused by a blown head gasket. Which technician is correct ?

Technician B only

A heater blows only cold air at operating temperature. Technician A states it must be a stuck closed thermostat. Technician B states the coolant system might be running low on coolant. Which technician is correct ?

A damaged compressor reed valve.

A manifold gauge indicates a system has low discharge pressure. The MOST likely cause of this condition is: A restricted condenser. A loose fan belt. A damaged compressor reed valve. A broken compressor piston.

Technician A only

A squeal is heard only when the compressor clutch first engages. Technician A says this is caused by a loose serpentine belt. Technician B says this is caused by a worn clutch pulley bearing. Which technician is correct ?

clogged screen or TXV stuck closed

A system with a low pressure on the low side and heavy frost accumulation on the inlet side of a TXV indicates what ?

Technician A only

A vehicle has poor air conditioning performance. The customer has added R134a refrigerant to the system. Technician A says to use a refrigerant identifier. Technician B says refrigerant mixtures are not recommended, but will not affect system pressures. Which technician is correct ?

Both Technician A & B

A vehicle with an EATC air conditioning system has low fan speed operation during high demand situations, like in direct sunlight. Technician A says this is because something is covering the sun load sensor's photo diode. Technician B says a sun load sensor is a variable resistor and can be tested with an ohmmeter. Which technician is correct ?

A missing fan shroud.

A vehicle's air conditioning performance is reduced at low speeds and stop lights, but cools at highway speeds. Which of these is MOST likely the cause of this condition? A low refrigerant charge. A missing fan shroud. A normal condition. A faulty compressor clutch relay.

The system still contains some refrigerant

After a recovery process, low-side pressure indicates above zero after five minutes. This condition means: A. The refrigerant system contains excessive oil B. There's a leak in the refrigerant system C. The system still contains some refrigerant D. There's an excess of moisture in the refrigerant system

Stuck open heater control valve

All of the following could cause poor heater performance EXCEPT ? A defective temperature blend door actuator. Radiator coolant temperature below 150° F (66° C) Heater core return hose much cooler than the inlet hose Stuck open heater control valve

Broken compressor reed valve

All of the following could cause the high side pressure in an AC system to be higher than normal, EXCEPT: a. Refrigerant overcharge b. Restricted condenser air flow c. Restricted evaporator air flow d. Broken compressor reed valve

Sight-glass diagnosis

All of the following diagnostic methods are used for many Automatic Air Conditioner systems, EXCEPT: a. Touch and Feel b. Self-Diagnosis process c. Scan tool d. Sight-glass diagnosis

A/C system and component problems do not produce diagnostic trouble codes.

All of the following statements about computer-controlled A/C system actuator motors are true EXCEPT: Some actuator motors are calibrated automatically in the self-diagnostic mode. A/C system and component problems do not produce diagnostic trouble codes. The actuator motor control rods must be calibrated manually on some systems. The actuator motor control rods should only require calibration after motor replacement or mis-adjustment.

Sealant is used to repair minor leaks.

All of the following statements are correct regarding AC system service, EXCEPT: a. Use a Refrigerant Identifier b. The service technician must be AC certified. c. Contaminated refrigerants are NEVER released to the atmosphere. d. Sealant is used to repair minor leaks.

B. Reuse existing compressor oil

All of these tasks occur when replacing the AC compressor EXCEPT: A. installing new seals and gaskets B. Reuse existing compressor oil C. Reuse all mounting brackets D. Use an equivalent or the same compressor

Moving the heat from inside the interior to outside of the vehicle.

An A/C system cools the interior of the vehicle by ?

Technician A only

An AC system is being identified. Technician A says that an accumulator located between the evaporator and the compressor indicates that the system has an orifice tube. Technician B says that when the high side service port fitting is smaller than the one on the low side the system uses R134A. Which technician is correct?

98 %

At what percentage (%) is refrigerant considered to be pure and safe for recovery?

True

Can a mixture of R12 and R134a result in higher than normal temperatures, which would subsequently cause damage to system components ? (True or False)

Both Technician A & B

During A/C system operation, a knocking sound can be heard coming from the compressor. Technician A says that there could be internal compressor damage. Technician B says that the compressor mounting brackets and bushings should be checked. Which technician is correct?

a faulty compressor.

During a performance test on a CCOT (Clutch Cycling Orifice Tube) system the manifold gauge indicates that the high side pressure is low and the low side pressure is high. This is caused by a ?

Faulty compressor.

During a performance test on a CCOT (Clutch Cycling Orifice Tube) system the manifold gauge indicates that the high side pressure is low and the low side pressure is high. This is caused by a ? Stuck open expansion valve. Frozen expansion valve. Restricted condenser. Faulty compressor.

Technician A only

During a performance test, technicians notice the compressor outlet is hot. Technician A believes this is normal. Technician B believes the system is overcharged. Which technician is correct ?

Technician B only

During the diagnosis of an ATC (Automatic Climate Control) system, a trouble code is obtained that references the blend door feedback sensor. Technician A says that the sensor should be replaced. Technician B says that the sensor circuit should be tested. Which technician is correct?

True

Fan speed does not increase as engine warms up is a cause for fan clutch replacement. (True or False)

True

Filters are installed to collect debris that could clog the orifice tube or expansion valve filters (True or False)

False

Filters are only installed in the high side of the system. (True or False)

True

Filters are usually installed in a system that has suffered compressor failure (True or False)

True

For a vapor to change back into a liquid, it must release a large amount of heat. (True or False)

R-134a

HFC-134a is also called ?

True

HOAT (Hybrid Organic Additive Technology) antifreeze uses both silicate and organic acid corrosion inhibitors for extended service life. (True or False)

The heat individuals feel.

Heat Intensity is what ?

True

High side pressure in a system is above spec. Overcharging the system can cause this. (True or False)

Water vapor content

Humidity refers to what in the air ?

True

IAT (Inorganic Additive Technology) antifreeze uses inorganic phosphates and silicates to provide corrosion protection. (True or False)

True

Is the ECT (Engine Coolant Temperature) sensor an NTC thermistor? (True or False)

True

Is the Inside Vehicle Temperature Sensor an NTC thermistor? (True or False)

False

Is the Sunload Sensor an NTC thermistor? (True or False)

Acid

Moisture can combine with the refrigerant to form what ?

True

Proper removal procedure of the Orifice Tube is being discussed. You are told to :- Cut out the section of line that contains the orifice tube and using a kit, install a new orifice tube segment. (True or False)

True

Quick-disconnect valves are used with R-134a refrigerant (True or False)

Light Blue

R-134a refrigerant is stored in what color container ?

True

R12 and R134a are in a gaseous state at room temperature. (True or False)

False

R134a is harmful to the ozone. (True or False)

False

R134a mixes with mineral oil. (True or False)

False

R134a operates at lower pressures than R12 (True or False)

True

Refrigerant has a boiling point below 32°F (0°C) (True or False)

Both Technician A & B

Technician A believes that a radiator needs to be inspected for leaks prior to installing a rebuilt engine. Technician B states that overheating during slower travel might be caused by the electric cooling fan fault. Which technician is correct ?

Both Technician A & B

Technician A says a defective thermostat can cause the engine to operate at too cold of a temperature. Technician B says if the thermostat is stuck closed it can make a pinging or banging sound. Which technician is correct ?

Technician B only

Technician A says evacuating an air conditioning system will remove air, debris, and moisture. Technician B says to evacuate the system any time it's been exposed to the atmosphere. Which technician is correct ?

Technician A only

Technician A says poor airflow through the heater core could cause a low heat complaint. Technician B says a high coolant level could cause a poor heat complaint. Which technician is correct ?

Both Technician A & B

Technician A says that moisture in the system can freeze in the expansion valve and stop the system from cooling. Technician B says that moisture in the system will react with R12 to form a corrosive acid. Which technician is correct?

Technician B only

Technician A says that the freezing point of a substance is the temperature at which the substance changes state from a solid to a liquid. Technician B says that the freezing point of a substance is the temperature at which the substance changes state from a liquid to a solid. Which technician is correct ?

Technician A only

Technician A says that the pressure cycling switch is usually located on the accumulator. Technician B says that the refrigerant must be recovered from the system before the switch can be removed. Which technician is correct?

Technician A only

Technician A says the clutch relay protects the control head from the clutch circuit's high current. Technician B says open clutch relay windings result in compressor clutch engagement at all times. Which technician is correct ?

Both Technician A & B

Technician A says the expansion valve is located on the inlet port of the evaporator. Technician B says the expansion valve's temperature sensing bulb is located near the outlet port of the evaporator. Which technician is correct ?

Neither Technician A nor B

Technician A says with a properly operating orifice-tube controlled AC system, the compressor inlet is hot to the touch and the outlet is cold to the touch. Technician B says the inlet to the evaporator is hot and the accumulator inlet is cold. Which technician is correct ?

Both Technician A & B

Technician A says you can find the refrigerant charge amount on a decal under the hood. Technician B says the best way to make sure the air-conditioning system is properly charged is to remove all refrigerant from the system and reinstall the proper amount of refrigerant. Which technician is correct ?

Technician A only

Technician A states that a misadjusted temperature door might cause poor heat. Technician B states that a defective resistor trio might cause the no high blower condition. Which technician is correct ?

Latent Heat

The "extra heat" needed to transform a substance from one state to the other is called ?

Both Technician A & B

The A/C compressor cycles rapidly, and air coming from the vents is only slightly cool. Technician A says the problem could be a low refrigerant charge. Technician B says the problem could be a defective thermostatic switch. Which technician is correct?

Compressor

The Accumulator is located between the Evaporator and ?

Before the Inlet to the Evaporator

The TXV (Thermostatic Expansion Valve) is located where in an A/C system ?

True

The TXV (Thermostatic Expansion Valve) requires a smaller refrigerant charge than the Orifice Tube system. (True or False)

Piston / Vane / Scroll

The basic designs of A/C Compressors include ?

True

The blower motor resistors are used to limit BOTH voltage and air-flow. (True or False)

Technician A only

The blower motor works on all speeds except low. Technician A says that this could be caused by an open in the 1.8-ohm resistor. Technician B says that this could be caused by an open in circuit 14S between the P/BL and P/0 splice and the motor. Which technician is correct?

Both Technician A & B

The carpet is wet on the passenger's side of a vehicle. Technician A says this may be caused by a leaking heater core. Technician B says this could be caused by a clogged evaporator case drain tube. Which technician is correct ?

True

The clutch must be removed and replaced to get to the compressor shaft seal . (True or False)

Both Technician A & B

The compressor cycles quickly and air coming from the vents is only slightly cool. Technician A says the problem could be a low refrigerant charge. Technician B says it could be a defective thermostatic switch. Which technician is correct?

Technician B only

The compressor in an A/C system does not run. When a jumper wire is used to connect the battery positive terminal to the power connector the clutch engages. Technician A says the clutch coil is bad. Technician B says the pressure cycling switch could be defective. Which technician is correct?

Both Technician A & B

The compressor is rapidly cycling on and off on a CCOT (Clutch Cycling Orifice Tube) air conditioning system. Technician A says this condition can be caused by a low refrigerant charge. Technician B says this could be caused by a faulty clutch cycling switch. Which technician is correct ?

Verify the customer concern

The first step in diagnostic procedure when attempting to solve an HVAC customer problem is ?

True

The operation of the Thermostatic Switch depends on the temperature of the Evaporator. (True or False)

Low Refrigerant Charge

The readings on a manifold gauge are 5 psi low and 80 psi high with the AC system operating at an ambient temp of 85°F. What do the readings indicate?

False

The rear A/C compressor is a part of the rear A/C system (True or False)

True

The receiver/drier is located in the high side of the system, between the condenser and evaporator, ahead of the expansion valve. It stores liquid refrigerant until needed by the evaporator. (True or False)

clogged or blocked restrictor.

The recirculate door is inoperable. Any of the following may be the problem EXCEPT a ? split, broken, or disconnected hose. clogged or blocked restrictor. restricted or open check valve. cracked or broken vacuum tank.

Red

The refrigerant identifier filter in the ACR4 machine must be visually checked every day. If the liquid refrigerant gets in the sample line, the filter is defective and will bleed what color dye? a. Black b. Gray c. Red d. Cloudy

True

The refrigerant used in automotive A/C systems from their inception until the early 90's was R12. More commonly known as Freon. (True or False)

Hot

The temperature of the refrigerant as it leaves the compressor on the Discharge Side should be what ?

an upper radiator hose collapsed after the engine was shut off.

The vacuum valve in the radiator cap is stuck closed. The result of this problem could be ? an upper radiator hose collapsed after the engine was shut off. excessive cooling system pressure at normal engine temperature. engine overheating when operating under a heavy load. engine overheating during extended idle periods.

True

There must be at least 50 psi of refrigerant pressure in the system in order for a leak detector to be able to sense a leak. (True or False)

the low side.

To charge an air conditioning system while it is running, the refrigerant should be added to the high side. the low side. both the high and low sides. either the high or the low side.

30 mins

To properly evacuate an AC system the vac pump should be run for ?

True

Touching the compressor seal with your finger during installation, may damage it. (True or False)

Technician B only

Two technicians are discussing O-rings. Technician A says that all O-rings are OK to use with the R-134a system. Technician B says that the color of the O-ring indicates the material it is made from. Which technician is correct ?

Technician B only

Two technicians are discussing a CCOT (Clutch Cycling Orifice Tube) air conditioning system. Technician A says the temperature cycling clutch switch contains a bulb placed on the inlet port of the evaporator core. Technician B says a pressure cycling switch is located on the low side of the system. Which technician is correct ?

Both Technician A & B

Two technicians are discussing an A/C system retrofit. Technician A says that a high pressure cut-out switch must be added. Technician B says the receiver drier should be replaced. Which technician is correct?

Both Technician A & B

Two technicians are discussing electric cooling fans and air conditioning performance. Technician A says electric fans regulate refrigerant temperatures more precisely than belt driven fans do. Technician B says electric cooling fans are controlled by temperature and pressure actuated switches. Which technician is correct ?

Both Technician A & B

Two technicians are discussing heat movement. Technician A says that heat is a form of energy. Technician B says that heat travels from hot to cold. Which technician is correct ?

Both Technician A & B

Two technicians are discussing refrigerant storage. Technician A says HFC-134a is contained in a sky blue container. Technician B says CFC-12 is contained in a white container. Which technician is correct ?

Both Technician A & B

Two technicians are discussing sight glass observations. Technician A says that if foam is seen in the sight glass, the refrigerant charge is low. Technician B says that if oil streaks are seen in the sight glass, the refrigerant charge is low. Which technician is correct?

Both Technician A & B

Two technicians are discussing variable displacement piston compressors. Technician A says that the Wobble Plate is moved to the high-angle position for maximum output when the cooling load is high. Technician B says that the Wobble Plate angle is controlled by the pressure in the crankcase of the compressor. Which technician is correct ?

Both Technician A & B

Using a DMM, technicians measure 12 volts at the clutch coil, but it doesn't engage. Technician A believes the bad clutch coil is the cause. Technician B believes that the bad clutch coil ground is the issue. Which technician is correct ?

True

Vacuum is measure in inches of mercury (Hg) (True or False)

True

Vehicles with Dual Zone climate control have a separate blend door for the passenger side of the vehicle. (True or False)

Both high and low-side are high

What high-side and low-side pressure gauge readings would a technician find if the condenser fan were inoperative? a. High-side high and low-side low b. High-side low and low-side high c. Both high and low-side are low d. Both high and low-side are high

50 psi

What is the minimum system pressure necessary to leak test with an electronic leak detector ?

Inadequate Lubrication

What is the most common cause of compressor failure ?

To switch the Compressor ON or OFF

What is the purpose of the clutch on an A/C compressor ?

True

When a system is retrofitted, the replacement receiver/drier or accumulator has XH-7 or XH-9 desiccant. (True or False)

the temperature and pressure increases

When a vapor is compressed, what happens to its temperature and pressure ?

The outlet to the Compressor

When an A/C system is operating, what part of the Compressor is hot to the touch ?

4 oz. (118.3 ml)

When replacing an A/C compressor, the refrigerant system is discharged and 2 oz. (59 ml) of oil is recovered from the system. When the old compressor is removed, 2 oz. (59 ml) of oil is drained from the compressor. The amount of oil drained from the new compressor is 6 oz. (177.4 ml). When the new compressor is installed, the amount of oil added to the compressor should be ? 1 oz. (29.6 ml) 2 oz. (59 ml) 4 oz. (118.3 ml) 6 oz. (177.4 ml)

True

When replacing the clutch hub the Air Gap should be checked in a number of different places (True or False)

High on both high and low pressure gauges

When the condenser airflow is restricted the pressure is which of the following? a. High side pressure low and low side pressure is low b. Low side pressure low and high side pressure is high c. High on both high and low pressure gauges d. Low side pressure high and high side pressure is low

Collapsed upper radiator hose after engine shut-down

When the vacuum valve in a radiator cap is stuck closed, which of the following could happen? a. High cooling system pressure at normal engine temperature b. Collapsed upper radiator hose after engine shut-down c. Engine overheating under heavy load d. Engine overheating during idle

Containers are sky blue colored.

Which is the correct statement about R 134a Refrigerant ? Changes from a vapor to a liquid as it absorbs heat. Containers are sky blue colored. Has a very high boiling point. Is a CFC that contains chlorine.

Permanently install conversion fittings using new hose clamps around the fittings.

Which of the following is not recommended while converting an R-12 system to R-134a? Permanently install conversion fittings using new hose clamps around the fittings. Install conversion labels and remove the R-12 label. Recharge the system with R-134a to approximately 80 percent of the original R-12 charge. Use a refrigerant identifier to make sure the system only contains R-12

The air is not cool enough.

Which of the following would happen if the air mix door motor is improperly positioned on an Automatic Air Conditioner system with an adjustable air mix door motor? a. The air is not cool enough. b. Air comes out the wrong vents. c. Defrost does not work. d. Air is stuffy.

Barrier Hose

Which type of refrigerant hose is used with an R-134a system ?

60%

While filling an A/C system recovery container with recovered refrigerant, the capacity you can fill the container would be: A. 50% B. 60% C. 70% D. 80%

Five (5) or Seven (7)

Wobble Plate Compressors commonly use how many cylinders ?

True

a Receiver Drier should be warm and the Accumulator should be cool. (True or False)

a low coolant level or a defective thermostat

lack of heat from the heater, would point towards ?

Both Technician A & B

During an A/C system performance test, high-side pressure was found to be excessive and the A/C compressor continued to run. Technician A says that the high-pressure cutout switch could be defective. Technician B says that there could be an air flow obstruction at the condenser. Which technician is correct?

Both Technician A & B

During an AC system test the high side pressure was found to be excessive and the compressor continued to run. Technician A says the high pressure cut out switch could be defective. Technician B says there can be an air flow obstruction at the condenser. Which technician is correct?

Technician A only

During an air conditioning performance test, the technician notices that the compressor outlet is hot. Technician A says this is a normal condition. Technician B says the air conditioning system is overcharged. Which technician is correct ?

False

High side pressure in a system is above spec. Could a broken compressor reed valve cause this. (True or False)

A clear sight glass indicates a fully charged or completely discharged system. If bubbles or foam are observed, this indicates a system that is not fully charged. An empty or low charged system may have oil streaks visible, as it was moved around by the remaining vapor. Sight glass is never used to diagnose an R134a system !

How does the sight glass be used to determine the state of charge of an HVAC system ?

True

If an R134a system has a sight glass, DO NOT use it to perform diagnosis. It is normal to observe bubbles in this type of system. (True or False)

fixed orifice tube system.

If the a/c system has an accumulator, it is a ?

Produce higher emissions

If the cooling system operates too cool, the engine will do what? A. Be less efficient B. Produce more torque C. Produce higher emissions D. Detonation

32 degrees Fahrenheit

In a properly working A/C system, the temperature of the Evaporator should be circa what ?

Dehumidifies the air

In addition to cooling the passenger compartment, an air-conditioning system does what ?

An air blend door is stuck.

In the vent position and with the temperature selector in the cool position, the incoming air is heated. What could be the problem? The cooling fan is inoperative. There is low coolant in the radiator. The heater core is clogged. An air blend door is stuck.

True

Is the OAT (Outside Air Temperature), commonly called the Ambient Air Temperature Sensor an NTC thermistor? (True or False)

True

It requires a large amount of heat to change a liquid into a gas. (True or False)

True

Low heater output can be caused by a restricted heater control valve (True or False)

True

Low heater output can be caused by an engine low on coolant (True or False)

False

Low heater output can be caused by disengaged clutch radiator fan (True or False)

True

Low heater output can be caused by stuck open thermostat (True or False)

Cabin Filter

Many late model cars use what to help clean the air in the vehicle ?

Absolute Humidity (AH)

Measurement of the weight of the water vapor in a given volume of air is called ?

True

Normal compressor repairs include replacing the Clutch Coil , Reed Valves, and Shaft Seal. (True or False)

True

OAT (Organic Additive Technology) antifreeze uses organic acids to protect then iron and aluminum in the cooling system. (True or False)

Neither Technician A nor B

Observing the data stream while operating a HVAC system on a late model vehicle the counts for the blend door change when the vehicle is moved outside in the mid day sun. Technician A says there is an intermittent problem with the blend door actuator that will eventually set a DTC. Technician B says that under no circumstances should the counts change on the blend door motor. Which technician is correct?

True

Often, the Pressure Cycling Switch is mounted on the Accumulator. (True or False)

True

Oil film on the back of the fan clutch is a cause for fan clutch replacement. (True or False)

True

Proper removal procedure of the Orifice Tube is being discussed. You are told to :- Disconnect the liquid line from the evaporator inlet and pull the orifice tube out with the extracting tool. (True or False)

True

R134a requires a different desiccant than R12. (True or False)

True

Receiver driers may have a sight glass at the top (True or False)

True

Receiver driers need to be replaced on any air-conditioning system that has been left open for any length of time (over 24 hours) (True or False)

Technician B only

There is a growling/rumbling noise at the AC compressor when the system is off and the engine is running. The noise stops when the system is turned on. Technician A says that a bad compressor bearing could be the cause. Technician B says that a bad compressor clutch bearing could be the cause. Which technician is correct?

A. the low side

To charge the air conditioning system while it runs, refrigerant must be added to: A. the low side B. the high side C. either side D. both sides

True

To check both high and low pressure service ports, normal readings should read Low 25-35/ high 150-200 psi. (True or False)

True

To check the performance of an A/C system, first turn the system on to maximum settings, and operate the engine @ 1500-2000 RPM with the doors open for 5-10 minutes. (True or False)

True

To prevent overfilling during transfer of refrigerant, never fill a container to more than 60 percent of its gross weight rating. (True or FALSE)

Excessive pressures

Too much oil in an A/C system will cause ?

The Orifice Tube system

What type of A/C system is depicted here ?

True

A Compressor that cycles on-and-off is usually used with an Orifice Tube System. (True or False)

Relative Humidity (RH)

A Hygrometer or Psychrometer measures what ?

TXV / Evaporator

A Receiver Drier is located between the Condenser and ?

Neither Technician A nor B

A customer with an SATC (Semi-Automatic Temperature Control) equipped vehicle complains that the car does not get cool enough on hot days. Technician A says that the blend door actuator is probably malfunctioning. Technician B says that the programmer is the problem. Which technician is correct?

Technician A only

A frozen spot is noticed in the center of the condenser. Technician A says a frozen spot on a component or connection indicates a restriction in the system. Technician B says this is caused by a clogged orifice tube. Which technician is correct ?

True

A major cause for the depletion of the ozone layer has been attributed to the release of CFCs (Chlorofluorocarbons) into the atmosphere. (True or False)

True

A new hose can be made up in the shop by installing the correct ends onto the right size, type, and length of hose. (True or False)

The engine thermostat being stuck open. If the engine is overheating or running at higher-than-normal temperatures, the mixture will be lean.

A port-fuel-injected engine has an excessively rich air:fuel ratio. This problem could be caused by engine overheating. a defective radiator cap. the engine thermostat being stuck open. the coolant control valve stuck open.

the engine thermostat being stuck open.

A port-fuel-injected engine has an excessively rich air:fuel ratio. This problem could be caused by ? engine overheating. a defective radiator cap. the engine thermostat being stuck open. the coolant control valve stuck open.

Technician B only

A technician is diagnosing a vehicle's air conditioning system. The vehicle has good engine performance, but the air conditioner is blowing warm air only. A yellow substance is noticed around the evaporator case drip tube. Technician A says this is coolant leaking from the heater core. Technician B says this is fluorescent dye leaking from the evaporator core. Which technician is correct ?

Recover and recharge the system

A technician is going to charge an AC system with R134a. Which of the following is the MOST accurate way to know the amount of refrigerant in the system? a. Recover and recharge the system b. Low side pressure stays at 50 PSI for R12 and 75 for R134a c. Recover the refrigerant into an EPA approved tank and weigh it d. High side pressure stays at 100 PSI for R12 and 125 for R134a

True

A typical TXV system has a bulb and / or capillary tube (Temperature Sensing Device) embedded in the evaporators fins or attached to the evaporator outlet pipe. (True or False)

Coolant Temperature

A typical control panel assembly controls all of the following EXCEPT the: compressor. heater valve. plenum door. coolant temperature.

True

A typical refrigerant identifier can detect all refrigerants EXCEPT R744 (which is pure CO2). (True or False)

Technician B only

A vacuum door actuator is being tested. When vacuum is applied with a hand held vacuum pump, the door does not move and the reading on the vacuum gauge is zero. Technician A says that the door does not move because it is binding or obstructed. Technician B says that the door does not move because the actuator is defective. Which technician is correct?

Technician B only

A vehicle with R134a refrigerant in the ac system has a refrigerant leak. Technician A says that a propane gas leak detector should be used to find the leak. Technician B says an electronic detector should be used. Which technician is correct?

A frozen expansion valve.

A vehicle's air conditioner blows cold air at normal speeds, but warm air while sitting at stop lights. The LEAST likely cause of this condition is: An overheating engine. A weak electric fan motor. A frozen expansion valve. Debris in the condenser fins.

170-200 PSI

Acceptable and good High Side pressure figures are ?

(Fail safe) The defroster is the default position in the event of failure with the vacuum supply.

Airflow flows from the defroster ducts, even though the selector lever is in other positions. Why ?

When stuck closed, pressure on high side is low and pressure on low side is high.

All of the following are true regarding the expansion valve, EXCEPT: a. When stuck closed, pressure on high side is low and pressure on low side is high. b. It can fail in the open position as a result of debris in the system. c. It can seize in the closed position due to a lack of lubricant. d. With moisture in the system, ice can form and cause blockage.

The refrigerant changes from a vapor to a liquid as it receives heat from the cabin air.

All of these statements are true about the automotive air-conditioners evaporator EXCEPT : a. It removes humidity from the air. b. Refrigerant flows from the bottom to the top. c. Refrigerant enters the evaporator as a liquid. d. The refrigerant changes from a vapor to a liquid as it receives heat from the cabin air.

a defective internal compressor bearing.

An A/C compressor has a growling noise only with the compressor clutch engaged. The cause of this noise could be a defective internal compressor bearing. a defective pulley bearing a low refrigerant charge. excessive refrigerant pressure.

475 psi (3,275 kPa).

An A/C compressor high-pressure release valve discharges refrigerant at approximately ? 200 psi (1,379 kPa). 325 psi (2,240 kPa). 375 psi (2,585 kPa). 475 psi (3,275 kPa).

Receiver-Drier

An Accumulator is very similar to what ?

Both Technician A & B

An air conditioning check has uncovered a discharge in the system and compressor damage. Technician A says that after the repairs are made, to check the low-pressure cutoff switch. Technician B says lubricating oil is carried by the refrigerant through the system. Which technician is correct?

A normal condition.

An air conditioning system contains a thermostatic expansion valve. The suction line leading to the compressor is cool to the touch. This indicates ? A stuck open expansion valve. A low refrigerant charge. A stuck closed expansion valve. A normal condition.

True

Any additional heat absorbed by the refrigerant above the Saturation Temperature (The temperature required to change the refrigerant from a liquid to a vapor) is called Superheat. (True or False)

moisture in the refrigeration system.

An A/C system blows cool air when the vehicle is started with an ambient temperature of 80 deg F (26.7 deg C). After the vehicle is driven for about 10 mi. (16 km), the system stops blowing cool air, and the thermal expansion valve (TXV) is frosted. When the A/C system is shut off for five minutes and turned on again, it blows cool air for another 10 mi. (16 km). The most likely cause of this problem is ? a defective thermal expansion valve (TXV) capillary tube. a refrigerant overcharge. a restricted condenser refrigerant passage. moisture in the refrigeration system.

True

Compressor Seal replacement can sometimes be done on the vehicle. (True or False)

True

Filters are installed to protect the new compressor from metal chips or other debris that could still be in the system (True or False)

False

Filters are only installed in the high side of the system (True or False)

The Expansion Valve would stick closed.

If a Capillary Tube were to break at some point between its sensing bulb and the Expansion Valve, what affect would it have on the valve?

False

Proper removal procedure of the Orifice Tube is being discussed. You are told to :- Disconnect the liquid line from the evaporator inlet line, then using a twisting motion, pull the orifice tube out with the extractor tool. (True or False)

True

R744 refrigerant is pure CO2 (True or False)

True

Receiver driers are located between the Condenser and TXV / Evaporator (True or False)

False

Receiver driers are used on systems using an orifice tube (True or False)

True

Receiver driers contain a desiccant to absorb moisture from the system (True or False)

False

Receiver driers keep liquid refrigerant from entering the compressor (True or False)

True

Receiver driers provide temporary storage for the liquid refrigerant (True or False)

True

Some cabin filters contain activated charcoal to absorb odors (True or False)

POA (Pilot Operated Absolute) /EPR (Evaporator Pressure Regulator)

The compressor operates continuously with which type of system controls ?

Technician A only

The engine cooling fan does not operate properly on a late model vehicle but works okay when the engine is hot in city driving. Technician A says there could be a problem with the engine computer. Technician B says there could be a problem with the engine temperature sensor. Which technician is correct ?

Verify customer concern

The first step in the diagnostic procedure when attempting to solve an HVAC customer problem is ?

Technician A only

The floor inside a vehicle is wet and there is a slimy film on the windows. Technician A says the heater core is leaking. Technician B says the evaporator case drain plug is clogged. Which technician is correct?

Both Technician A & B

The in-cabin temperature sensor is suspected for an air conditioner's poor performance. Technician A says the in-cabin temperature sensor is a NTC that should be tested for resistance with an ohmmeter. Technician B says the aspirator may be disconnected from the vent system. Which technician is correct ?

Both Technician A & B

The inside of an EATC (Electronic Automatic Temperature Control) equipped vehicle never feels as cool as the temperature setting. The A/C system checks out OK, including the sensors. Technician A says there could be an obstruction in the aspirator tube. Technician B says the aspirator tube could be disconnected from the duct. Which technician is correct?

Verify the repair

The last step in the diagnostic procedure is ?

the filter/dryer cartridge on the tester must be changed.

The moisture warning light on the recovery/recycling equipment indicates yellow during the recycling process. This indicates: there is excessive oil in the refrigerant. the filter/dryer cartridge on the tester must be changed. there are excessive non-condensable gases in the refrigerant. the vacuum pump is not producing enough vacuum.

The filter/drying cartridge on the tester needs to be changed

The moisture warning light on the recovery/recycling equipment shows yellow in the recycling process. This shows: A. The filter/drying cartridge on the tester needs to be changed B. There is excessive amounts of oil found in the refrigerant C. The vacuum pump can't produce enough vacuum D. There are excessive amounts of non-condensable gases in the refrigerant

True

The temperature required to change the refrigerant from a liquid to a vapor is known as the Saturation Temperature. (True or False)

TXV (Thermostatic Expansion Valve)

The variable valve that changes the size of the valve opening in response to the cooling load of the evaporator is called ?

The clutch would engage whenever powered.

There is a short to ground at point D of the electrical diagram above. Which of the following statements is true? The clutch would not engage when powered. The relay would remain open. The PCM would not receive a signal from the clutch. The clutch would engage whenever powered.

False

When the engine is hot, the fan stops spinning in only two seconds after shut down is a cause for fan clutch replacement. (True or False)

Technician B only

When troubleshooting an AC system the system responds when the ambient and in-vehicle temp sensors are heated and cooled. However there is no response when the sun-load sensor is exposed to a light source. Technician A says that the problem is with the system's programmer. Technician B says it is probably the sun-load sensor. Which technician is correct?

Condenser Outlet

Where in the AC system is the refrigerant a high-pressure liquid ?

Evaporator Outlet

Where in the AC system is the refrigerant a low-pressure gas ?

PAG

Which of the following oils can be used in a R-134a system? mineral oil CCOT (Clutch Cycling Orifice Tube) ester oil PAG

ND-11

Which of the following refrigerant oil is recommended for use in a hybrid electric compressor? a. ND-10 b. ND-11 c. ND-9 d. ND-8

Incorrect air gap

A compressor clutch will not engage. Power and ground at the clutch coil are good. Which of the following is the MOST likely cause? a. Low refrigerant b. Locked-up compressor c. Incorrect air gap d. Bad pressure cycling switch

Stuck expansion valve

A concern of intermittent AC cooling is being diagnosed. The gauge set shows intermittently high and low side pressure gauge readings and the high side intermittently drops to 100 psi. Which of the following is the MOST likely cause? a. Stuck expansion valve b. Overcharged A/C System c. Compressor internal leak d. Damaged compressor reed valve

Compressor

A technician is checking for a properly operating AC system using an infrared thermometer. The outlet should be hot from which of the following A/C components? a. Expansion valve b. Accumulator c. Compressor d. Orifice tube

Check for technical service bulletins

A technician is checking the blower motor operation on a manual AC system with the engine running and at normal operating temperature. The blower motor speed does not increase above low. Which of the following actions should the technician take first? a. Check blower motor circuit b. Check for technical service bulletins c. Replace high blower relay d. Adjust the temperature door

Technician A only

A technician is using the owner's manual to check the manual control system operation. Technician A says for quick heating the air recirculation button should be in the "on" position. Technician B says the AC should never be "on" when the temperature control is in the "hot" position. Which technician is correct ?

Solar or sun load sensor

A vehicle with an automatic air conditioning and heating system has a customer concern of reduced blower speed. Which of the following is the MOST likely cause? a. Recirculation door b. Heater door c. Solar or sun load sensor d. Ambient sensor

Type and mixture as required in the service information

After flushing the engine coolant, you refill the system with which of the following coolant mixtures? a. 50% ethylene glycol and 50% propylene glycol b. 75% antifreeze and 25% water c. Type and mixture as required in the service information d. 50% water and 50% antifreeze

Engine running at 3,500 rpm

All of the following are steps to an AC performance test, EXCEPT: a. Air conditioning set to ON and blower speed be set to HIGH b. Engine running at 3,500 rpm c. Temperature set to maximum cool with all doors open d. Mode control set to recirculation

Clutch air gap

All of the following could cause compressor drive belt edge wear, EXCEPT: a. Clutch air gap b. Bent mounting bracket c. Damaged pulley d. Worn pulley bearing

Internal compressor damage

All of the following issues are present with a cracked AC compressor mounting plate, EXCEPT: a. Drive belt wear b. Internal compressor damage c. Compressor vibration d. Drive belt squeal

To avoid outside odor, operate AC System in Normal rather than Recirc mode.

All of the following statements are correct regarding an air conditioning performance test, EXCEPT: a. Road debris can clog the condenser fins reducing system performance. b. To avoid outside odor, operate AC System in Normal rather than Recirc mode. c. Passenger-side floor being wet is one symptom of a clogged evaporator drain line. d. Obstructions of the cabin air filter may cause insufficient air circulation.

Reuse same compressor oil

All of the following tasks are performed when replacing an AC compressor, EXCEPT: a. Reuse all mounting brackets b. Use new gaskets and seals c. Use the same or equivalent compressor d. Reuse same compressor oil

Excessive refrigerant charge

Both high and low-pressure sides are too high. The pressure is reduced after water is splashed on the condenser. Which of the following could be the cause? a. Stuck open TXV (Thermal expansion valve) b. Stuck closed TXV (Thermal expansion valve) c. Excessive refrigerant charge d. Insufficient refrigerant charge

Duct air leaks

During the operation check of a manual AC control system, the temperature does not increase. All of the following could cause this condition, EXCEPT: a. Thermostat stuck open b. Engine coolant level low c. Mix door operation d. Duct air leaks

C. Air blend door is stuck.

Incoming air is heated in the vent position with the temperature selector in the cool position. What might be the problem? A. Heater core is clogged. B. Cooling fan is inoperative. C. Air blend door is stuck. D. Low coolant in the radiator.

High-side readings 199-228 psi; Low-side readings 21-36 psi

Normal AC pressure gauge readings on a day with an outside temperature of 90° F should fall within which of the following? a. High-side and low-side readings about the same 50-100 psi b. High-side and low-side readings about the same 100-200 psi c. High-side readings 100-250 psi; Low-side reading 35-40 psi. d. High-side readings 199-228 psi; Low-side readings 21-36 psi

Technician A only

On a manual air conditioning system without automatic control, the compressor clutch does not operate. Technician A says there is a failed compressor thermal protector. Technician B says there is an incorrectly adjusted temperature door. Which technician is correct ?

Technician A only

Technician A says R12 and R134a may be recycled in your shop; most other refrigerants must be recovered and sent to a waste disposal facility. Technician B says all refrigerants do not need to be recovered. Which technician is correct ?

Technician A only

Technician A says a misadjusted temperature door could cause a poor heat complaint. Technician B says a defective resistor trio can cause a no high blower condition. Which technician is correct ?

Both Technician A & B

Technician A says a radiator should always be inspected for leaks before installing a rebuilt engine. Technician B says overheating during slow in-town driving can be caused by an electric cooling fan fault. Which technician is correct ?

Technician A only

Technician A says pressure gauges on an R134a system are connected to 2 different service ports, colored blue for the low-pressure side and colored red for the high-pressure side. Technician B says you test for R134a pressure with the engine off. Which technician is correct ?

Technician B only

Technician A says removing the thermostat from the coolant system will repair an overheating concern. Technician B says poor airflow through the heater core could cause a blower motor resistor to burn out. Which technician is correct ?

Both Technician A & B

Technician A says that after a compressor failure it is a good idea to add an additional filter designed to catch a small amount of debris that may still be in the system from the compressor failure. Technician B says that additional filters are generally placed in the liquid line after the condenser, but before the restriction. Which technician is correct ?

Technician A only

Technician A says the cooling system should be tested for leaks using a hand operated pressure tester. Technician B says the freezing temperature of the coolant can be tested using a thermometer. Which technician is correct ?

Technician B only

The heater blows out only cold air at operating temperature. Technician A says a stuck closed thermostat could be the cause. Technician B says the cooling system could be low on coolant. Which technician is correct ?

DLC (Data Link Connector)

To which of the following devices does a technician connect a scan tool or laptop computer to diagnose an AC system? a. BCM (Body Control Module) b. STAICE (Simplified Test Approach Internal Combustion Engine) c. DLC (Data Link Connector) d. PCM (Power Train Control Module)

Technician B only

Two technicians are explaining refrigerant recycling. Technician A says refrigerants are checked for condensable gases such as air. Technician B says a shop must have certified technicians doing AC service. Which technician is correct ?

Recovery

What process listed below removes all R12 or R134a refrigerant from a system and then stores it in an external EPA approved tank? a. Recovery b. Recycling c. Reclaiming d. Removal

Before any service

When should R134a refrigerant be checked for contamination? a. Before any service b. After recycling c. Before charging d. After charging

True

When the defrost setting is selected, the compressor operates. (True or False)

Ground

When using the voltmeter function of a Digital Multimeter (DMM), the black lead is connected to which of the following? a. Positive side of circuit b. Non-conductive surface of battery c. Ground d. At any location

Clogged radiator

Which of the following conditions is the MOST likely cause of a vehicle overheating? a. Electric cooling fan runs all the time b. Restricted heater core c. Thermostat stuck open d. Clogged radiator

Air

Which of the following is a non-condensable gas? a. Air b. R-12 c. Atmospheric Ozone d. R-134a

Disconnect battery negative cable

Which of the following is the first and most important step when disabling the air bag to service an AC system? a. Disconnect battery negative cable b. Disconnect clock-spring electrical connector c. Check resistance at the clock spring connector d. Disconnect the seat position sensors

Check the coolant level in overflow bottle and radiator.

Which of the following is the first step in bleeding a cooling system? a. Run the engine between idle and 4,000 RPM. b. Start the engine and bring it to operating temperature. c. Check the coolant level in overflow bottle and radiator. d. Look for air bubbles in the reservoir and listen for air.

True

Accumulators are used in systems with orifice tubes, not expansion valves. (True or False)

Missing air dam

All of the following could cause lower than normal high-side pressure EXCEPT ? Missing air dam Low refrigerant charge Worn Compressor Restricted orifice tube

True

Are there filters that fit into both the high and low sides of the system (True or False)

a leaking heater core.

A customer complains about engine coolant loss. The cooling system is pressurized at 15 psi (103 kPa) for 15 minutes. There is no visible sign of coolant leaks in the engine or passanger compartments, but the pressure on the tester gauge decreases to 5 psi (34 kPa). This problem could be caused by any of the following defects EXCEPT : a leaking heater core. a leaking transmission cooler. a leaking head gasket. a cracked cylinder head.

Technician B only

A CCOT (Clutch Cycling Orifice Tube) system has a high high side. Technician A says to suspect the thermostatic expansion valve. Technician B says this system contains an orifice tube. Which technician is correct ?

Both Technician A & B

A TXV (Thermostatic Expansion Valve) system blows cold air for five minutes and then goes warm. Technician A says this condition is caused by a low refrigerant charge. Technician B says this condition is caused by moisture in the system. Which technician is correct ?

Technician B only

A blower motor operates only in high speed. Technician A says there could be a short in the motor's power feed. Technician B says it may have a faulty blower motor resistor. Which technician is correct ?

Technician B only

A compressor clutch coil is being tested. There are 12 volts at the connector and the ground is good. The resistance of the coil is 0.00 Ohms. Technician A says the coil has an open in it's windings. Technician B says the clutch coil has a short and has failed the resistance test. Which technician is correct ?

A restricted heater core

A customer comes in with the complaint that the heater will not blow warm air. It blows cold air when engaged. All fan speed settings work, however the temperature never increases. Which of the following issues is most likely to blame? Bad refrigerant in the HVAC system A restricted heater core A stuck open thermostat A faulty heater switch

True

According to the Clean Air Act, recovery / recycling equipment must have shutoff valves located within 12 in. of the hoses' service ends so that refrigerant discharge to the atmosphere is kept to a minimum. (True or False)

Both Technician A & B

A customer complains of a foul odor coming from the dash outlets whenever the A/C and blower are on. Technician A says that this is caused by a clogged evaporator drain. Technician B says that this is caused by bacterial growth on the evaporator. Which technician is correct?

Technician B only

A customer complains that the heater works sometimes, but sometimes only cold air comes out while driving. Technician A says that the water pump is defective. Technician B says that the cooling system could be low on coolant. Which technician is correct?

Technician B only

A customer has a complaint of poor heat output. After checking the hoses running to and from the heater core, the technician finds them both to be hot. Technician A says the problem could be a clogged heater core. Technician B says a mis-adjusted temperature control cable could be the problem. Which technician is correct?

Blocked or clogged restrictor

A recirculate door isn't working. All of these might be the cause EXCEPT: A. Blocked or clogged restrictor B. Disconnected, broken or split hose C. Open or restricted check valve D. Broken or cracked vacuum tank

Recycle the refrigerant in the container

A refrigerant container has been found to have pressure above the maximum for its temperature. What should the technician do ?

True

A vacuum pump removes water from the air conditioning system by boiling it. (True or False)

Neither Technician A nor B

A vehicle comes into the shop with a complaint of "no cold air". Technician A says to first turn the key off, set the DVOM to DC volts and measure the voltage present at the electromagnet clutch. If there is no voltage present, replace the compressor. Technician B says set the DVOM to DC volts and measure the continuity of the compressor clutch. Which technician is correct?

25-35 PSI

Acceptable and good Low Side pressure figures are ?

There is still some refrigerant in the system.

After the recovery process, the low-side pressure increases above zero after five minutes. This condition indicates: There is still some refrigerant in the system. there is excessive oil in the refrigerant system. the refrigerant system is leaking. there is excessive moisture in the refrigerant system.

Technician B only

Airflow through a typical HVAC system is being discussed. Technician A says that outside air is always used in all heating and cooling positions. Technician B says that the temperature is controlled by blending airflow through the evaporator and heater core. Which technician is correct?

Technician B only

Airflow through a typical HVAC system is being discussed. Technician A says that outside air is always used in all heating and cooling positions. Technician B says that the temperature is controlled by blending air flow through the evaporator and heater core. Which technician is correct?

Any size and type of refrigerant storage container over 10 lb. (4.8 kg) may be used in this equipment.

All of the following statements about A/C recovery/recycling equipment are true EXCEPT: The equipment label must indicate UL approval. The equipment label must indicate SAE J1991 approval. Any size and type of refrigerant storage container over 10 lb. (4.8 kg) may be used in this equipment. R-12 and R-134a refrigerants or refrigerant oils must not be mixed in the recovery/recycling process.

The refrigeration system must be discharged before the A/C control panel is removed.

All of the following statements about A/C-heater control panel service are true EXCEPT: The negative battery cable must be disconnected before A/C control panel removal. The refrigeration system must be discharged before the A/C control panel is removed. If the vehicle is air-bag-equipped, wait the specified time period after negative battery cable disconnected. Self-diagnostic tests may indicate a defective A/C control panel in a computer-controlled A/C system.

When the cooling system pressure is increased, the boiling point is decreased.

All of the following statements about cooling system service are true EXCEPT: When the cooling system pressure is increased, the boiling point is decreased. If more antifreeze is added to the coolant, the boiling point is increased. A good quality ethylene glycol antifreeze contains anti-rust and corrosion inhibitors. Coolant solutions must be recovered, recycled, or handled as hazardous waste.

The throttle kicker is an electronic device that is typically part of the TP sensor.

All of the following statements are correct EXCEPT When the A/C compressor engages, it requires increased effort from the engine to run the compressor. This increased effort causes a lower rpm at idle. The throttle kicker is an electronic device that is typically part of the TP sensor. A leaking throttle kicker diaphragm or an inoperative kicker solenoid may cause lower than specified idle rpm and engine stalling with the A/C on. The throttle kicker maintains idle speed during warm-up.

This system contains a thermostatic expansion valve to meter the refrigerant

All of these are true about an accumulator EXCEPT: It is located on the low side of the system. It prevents excess liquid from entering the compressor. It contains a desiccant capable of absorbing moisture from the refrigerant. This system contains a thermostatic expansion valve to meter the refrigerant

If stuck closed, the pressure on the low side is high and pressure on the high side is low

All of these statements are accurate in relation to the expansion valve, EXCEPT: A. When it fails in the open position, it's often a result of debris in the system B. When moisture enters the system, ice might form and lead to a blockage C. If stuck closed, the pressure on the low side is high and pressure on the high side is low D. It might seize in the closed position if it doesn't have enough lubricant

A/C component and system troubles don't produce diagnostic trouble codes

All of these statements regarding the computer-controlled A/C system actuator motor are correct EXCEPT: A. A/C component and system troubles don't produce diagnostic trouble codes B. Some actuator motors are automatically calibrated in the self-diagnostic mode C. The actuator motor control rods only require calibration once the motor has been misadjusted or replaced D. Actuator motor control rods must be manually calibrated with some systems

The ECM (Electronic Control Module) disengages the A/C clutch at idle.

All these statements are true about a throttle position sensor EXCEPT: It indicates throttle position to the engine control module. The control module disengages the A/C clutch at wide open throttle. The ECM (Electronic Control Module) disengages the A/C clutch at idle. The throttle position sensor signal is used to indicate throttle angle.

True

An Evacuation is done with both manifold valves open. (True or False)

Both Technician A & B

An air conditioner with an expansion valve performs poorly only during the hottest times of the day. Technician A says the receiver drier may be saturated. Technician B says there may be moisture in the refrigerant. Which technician is correct ?

Both Technician A & B

An air conditioning system blows only warm air when the heater is on high output. Technician A says this could be a faulty heater control valve. Technician B says this could be caused by the cooling system's thermostat. Which technician is correct ?

TXV (Thermostatic Expansion Valve)

Identify this component

True

CFC's have been found to have a devastating effect on the Earths Ozone Layer. (True or False)

False

Can R12 and R134a be mixed ? (True or False)

True

Desiccants are not universal and different types must be used with different refrigerants and lubricating oils (True or False)

Restricted condenser

During a A/C system performance test, the air temperature at the center outlet duct is warm to slightly cool and the low and high side pressures on the manifold gauge set are both low. All of the following could be the cause EXCEPT ? Clogged orifice tube Expansion valve stuck closed Restricted receiver/ drier Restricted condenser

Technician A only

During a visual inspection an oily spot is found on a hose leading from the compressor. Technician A says there may be a refrigerant leak in the system. Technician B says today's R134a systems use mineral oil instead of the older R12 compatible PAG oil. Which technician is correct ?

A restriction in the receiver drier.

During an initial inspection, the technician notices that one line on the receiver drier is cooler than the other. This is caused by ? Nothing it's a normal condition. A low refrigerant charge. Too much oil in the system. A restriction in the receiver drier.

Calories / BTU

Heat is measured in _________________ or ___________________ ?

True

High side pressure in a system is above spec. A slipping fan belt can cause this. (True or False)

True

High side pressure in a system is above spec. Restricted air flow across the condenser can cause this. (True or False)

When your engine starts over heating and surpasses normal operating temperature.

How do you know you have a defective thermostat ?

The oil moves through the system, simply with the movement of the refrigerant.

How is the A/C Compressor lubricated in an R-134a system ?

45-55 %

Humans prefer relative humidity that is?

68-78° F

Humans prefer temperature that is ?

True

New refrigerant oil should be added to condenser and accumulators as they are installed. (True or False)

True

No viscous drag is a cause for fan clutch replacement. (True or False)

Both Technician A & B

Nothing is seen in the sight glass. Technician A says that the system may be completely empty of refrigerant. Technician B says that the system may be completely charged. Which technician is correct?

a loose power steering belt

On a vehicle with V-belts, an intermittent squealing noise is heard on acceleration with the A/C control switch in the on or off position. The most likely cause of this problem is ? a loose power steering belt a loose A/C compressor belt. a loose air pump belt. a worn A/C compressor pulley bearing.

Technician B only

Technician A says a fixed orifice tube varies the flow of refrigerant in relation to temperature. Technician B says a fixed orifice tube is located between the condenser and the evaporator. Which technician is correct ?

Technician B only

Technician A says a fixed orifice tube varies the flow of refrigerant in relation to temperature. Technician B says a fixed orifice tube is located between the condenser and the evaporator. Which technician is correct ?

Technician B only

Technician A says a special tool is needed to disconnect and connect spring lock fittings. Technician B says when assembling spring lock fittings new O rings lubricated with clean refrigerant oil should be used. Which technician is correct?

Technician B only

Technician A says an ambient temperature sensor senses cabin air temperature. Technician B says a faulty ambient temperature sensor can prevent compressor clutch engagement. Which technician is correct ?

Both Technician A & B

Technician A says refrigerant flows from the top of the condenser to the bottom. Technician B says a restriction in a condenser can cause damage to the compressor. Which technician is correct ?

Both Technician A & B

Technician A says that an ambient temperature switch protects the compressor from damage. Technician B says that an ambient temperature sensor provides input for the ATC (Automatic Temperature Control) system. Which technician is correct?

Technician A only

Technician A says that evacuating an AC system will remove air and moisture from the system. Technician B says evacuating an AC system removes dirt particles. Which technician is correct?

Both Technician A & B

Technician A says that evaporator leaks can be detected by installing dye into the system and looking for yellowish-green dye stains. Technician B says that a leak at the evaporator can be detected by removing the blower motor resistor pack and inserting an electronic leak detector probe into the air stream. Which technician is correct?

Technician B only

Technician A says that heat is measured in degrees. Technician B says that temperature is measured in degrees. Which technician is correct?

Technician B only

Technician A says that mineral deposits can restrict air flow through the radiator. Technician B says that internal restrictions in the radiator can be detected from the outside. Which technician is correct?

Technician B only

Technician A says that one heater hose should be hot and the other hose cool if the heater is functioning okay. Technician B says that both hoses should be hot to the touch. Which technician is correct?

Both Technician A & B

Technician A says that the A/C system can be charged through the high or low side only when the engine is not running. Technician B says that the A/C system can be charged though the low side when the engine is running. Which technician is correct?

Technician A only

Technician A says that when retrofitting an A/C system, the new R134a ports are installed on the old fittings. Technician B says that if the old fittings are not converted they should be labeled. Which technician is correct?

Technician A only

Technician A says that when there is a "U" DTC (Diagnostic Trouble Code), it should be repaired before any further diagnostics can be performed. Technician B says that a "U" DTC (Diagnostic Trouble Code) indicates there is nothing wrong with the AC system. Which technician is correct?

Both Technician A & B

Technician A says that with a properly operating air-conditioning system, the inlet to the compressor should be cold and the outlet from the compressor hot. Technician B says that the condenser should be hot and the evaporator cold. Which technician is correct?

Both Technician A & B

Technician A says the expansion valve is located on the inlet port of the evaporator. Technician B says the expansion valve's temperature sensing bulb is located near the outlet port of the evaporator. Which technician is correct ?

Both Technician A & B

Technician A says to measure the Sunload Sensor signal you must use a DVOM and measure its signal voltage changes. Technician B says to use a scan tool and observe the data stream to see the counts change when the light is varied to the sensor. Which technician is correct?

Technician A only

Technician A says while performing a retrofit from R-12 refrigerant to R134a refrigerant, the refrigerant must be recovered into a dedicated cylinder, they cannot be mixed. Technician B says R-12 refrigerant functions at higher pressures than R-134a refrigerant does. Which technician is correct ?

True

The Orifice Tube system is simpler and cheaper to produce than the TXV (Thermostatic Expansion Valve) system (True or False)

True

The Pressure / Temperature Cycling Switch in conjunction with a TXV engages / disengages the Compressor Clutch. (True or False)

True

The Pressure / Temperature Cycling Switch is mounted on the Accumulator in a Fixed Orifice Tube system. (True or False)

Desiccant

The Receiver Drier or the Accumulator contains what to remove moisture from the system ?

True

The Sunload Sensor is a Photo-voltaic Diode. (True or False)

True

The accumulator is the component that keeps liquid refrigerant from entering the compressor. (True or False)

Technician B only

The ambient temperature sensor in an EATC (Electronic Automatic Temperature Control) system is being tested. Technician A says that the resistance of the sensor should increase as it is heated. Technician B says that, as the sensor resistance changes, the computer reads the change in voltage drop across the sensor. Which technician is correct?

The air temperature

The amount of water that air can hold depends on what ?

the compressor coil positive wire is shorted to a 12 volt source.

The compressor clutch will not disengage. The problem could be that: the A/C pressure cutoff switch is stuck open. the compressor clutch coil is shorted to ground. the low-pressure switch has an open wire. the compressor coil positive wire is shorted to a 12 volt source.

Technician A only

Two technicians are discussing an inoperative electric blend door in an automatic air conditioning system. Technician A says to inspect the blend door's wiring and connections for an open circuit. Technician B says to troubleshoot this circuit with a test light. Which technician is correct ?

Install dye in the system

What must the technician do before checking an air-conditioning system for refrigerant leaks using a black light?

R-1234yf

What refrigerant is sold in a white container with a red stripe ?

The TXV (Thermostatic Expansion Valve) system

What type of A/C system is depicted here ?

Both Technician A & B

When an A/C system is operating a clicking or buzzing is heard from the compressor. Technician A says the system is overcharged. Technician B says the noise is due to air in the system. Which technician is correct?

if the pressure is lower than specified, the refrigerant is ready for use.

When checking a refrigerant container for non-condensable gases: the container may be stored at 80 deg F (27 deg C) for six hours before the test. the container may be stored near a shop window. a thermometer should be placed against the container surface. if the pressure is lower than specified, the refrigerant is ready for use.

Technician B only

When checking recycled refrigerant for excess non-condensable gases (air). Technician A says that the container must be stored at 65°F (18°C) or above for 8 hours out of direct sunlight, before checking the pressure. Technician B says if the pressure is higher than the limit shown for a given temperature, there is air in the tank. Which technician is correct?

80-90%

When converting the A/C system in an older vehicle to R134a what percentage of the original R12 charge amount should be used ?

Resistance and Voltage Drop

When diagnosing an ATC system, most of the system temperature sensors can be tested for ? Resistance and Current Flow Resistance and Voltage Drop Voltage Drop and Current Flow Current Flow and Continuity

60 %

When filling a container with recycled refrigerant to what percentage % should the container be filled?

60 percent

When filling an A/C system recovery container with recovered refrigerant, the percentage of capacity that the container may be filled to is 50 percent 60 percent 70 percent 80 percent

Technician A only

When pressure testing the cooling system on a late model gas engine, the pressure on the tester drops but no leaks can be found in the engine compartment. Technician A starts the engine and seeing the pressure on the tester increase, says that there is an internal leak, a blown head gasket. Technician B says that there cannot be an internal leak because the engine oil looks normal, not milky like it would be if coolant were present, and there is no white smoke coming from the exhaust pipe. Which technician is correct ?

5 min.

When recovering refrigerant from an AC system how long should the technician wait after the recover/recycle unit has been turned off to check residual pressure in the system?

True

When refrigerant containers are filled, reserve room is left for expansion and the container marked with its critical temperature. (True or False)

Technician B only

When replacing a blend door actuator... Technician A says that after installing the actuator, the control module will automatically know what step the actuator is on and there is no need for calibration. Technician B says that after replacing the actuator, one procedure for re-calibrating the control module would be to remove the fuse for the module for at least 60 seconds, then replace the fuse and perform an operational test of the system. Which technician is correct?